Install ModSecurity on Apache for Ubuntu: A Comprehensive Guide
You install ModSecurity on Apache for Ubuntu to enable a robust web application firewall (WAF) for enhanced server security.
ModSecurity, often shortened to ModSec, acts as a crucial security layer that inspects incoming HTTP traffic. It actively blocks malicious requests, such as those attempting SQL injection or cross-site scripting (XSS), before they can harm your web applications.
This guide focuses on integrating ModSecurity version 3.0.10 with Apache 2.4 on Ubuntu 22.04 LTS, a powerful setup to defend your web server.
You will learn to configure ModSecurity effectively to protect your Apache web applications from common online threats.
Install ModSecurity and the Apache module using `sudo apt update` and `sudo apt install apache2 libapache2-mod-security2`. Enable the module with `sudo a2enmod security2` and reload Apache.
How to install ModSec with Apache on Ubuntu Linux
As described above, ModSec is an open-source web application firewall (WAF). Initially developed as a module on Apache, it is now a full-fledged WAS supporting Nginx and IIS.
Below is how to install it with the Apache HTTP server.
Install ModSecurity and Apache
Installing ModSecurity for Apache on Ubuntu is straightforward using terminal commands.
sudo apt update sudo apt install apache2 libapache2-mod-security2
To check that ModSec is installed, run the commands below.
apachectl -M | grep security
The command above should output a line below.
security2_module (shared)
If it’s not enabled, you can enable the module by running the commands below.
sudo a2enmod security2 sudo systemctl reload apache2
Configure ModSecurity
To make ModSecurity actively block threats on your Apache server running Ubuntu, you’ll need to change its main settings file.
You’ll find the default configuration file at /etc/modsecurity/modsecurity.conf-recommended. To start customizing, copy this file and rename it modsecurity.conf.
sudo cp /etc/modsecurity/modsecurity.conf-recommended /etc/modsecurity/modsecurity.conf
Next, run the commands below to open the newly created config file.
sudo nano /etc/modsecurity/modsecurity.conf
Change the highlighted lines in the file from DetectionOnly to On.
# -- Rule engine initialization ---------------------------------------------- # Enable ModSecurity, attaching it to every transaction. Use detection # only to start with, because that minimises the chances of post-installation # disruption. # SecRuleEngine On # -- Request body handling --------------------------------------------------- # Allow ModSecurity to access request bodies. If you don't, ModSecurity # won't be able to see any POST parameters, which opens a large security # hole for attackers to exploit. SecRequestBodyAccess On # Enable XML request body parser. # Initiate XML Processor in case of xml content-type
Save and exit, then restart Apache.
sudo systemctl restart apache2
Add OWASP ModSecurity rules
Adding the OWASP Core Rule Set (CRS) to your ModSecurity setup on Ubuntu provides strong, recommended security rules to protect your web applications.
Clone the latest OWASP CRS from GitHub to the /usr/share/ directory by running the commands below.
sudo rm -rf /usr/share/modsecurity-crs sudo git clone https://github.com/SpiderLabs/owasp-modsecurity-crs.git /usr/share/modsecurity-crs
Next, rename the example file to crs-setup.conf.
sudo mv /usr/share/modsecurity-crs/crs-setup.conf.example /usr/share/modsecurity-crs/crs-setup.conf
Next, run the commands below to open the ModSec security configuration file.
sudo nano /etc/apache2/mods-enabled/security2.conf
Then, edit the highlighted lines to enable the OWASP rules we downloaded above.
<IfModule security2_module>
# Default Debian dir for modsecurity's persistent data
SecDataDir /var/cache/modsecurity
# Include all the *.conf files in /etc/modsecurity.
# Keeping your local configuration in that directory
# will allow for an easy upgrade of THIS file and
# make your life easier
IncludeOptional /etc/modsecurity/*.conf
# Include OWASP ModSecurity CRS rules if installed
IncludeOptional /usr/share/modsecurity-crs/*.conf
IncludeOptional /usr/share/modsecurity-crs/rules/*.conf
</IfModule>Save and exit.
Restart Apache and you’re good to go.
sudo systemctl restart apache2
To test that ModSec is running, run the commands below.
curl 'http://127.0.0.1/test.html?a=<script>alert(1);</script>'
You should get an output message similar to the one below:
<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN"> <html><head> <title>403 Forbidden</title> </head><body> <h1>Forbidden</h1> <p>You don't have permission to access this resource.</p> <hr> <address>Apache/2.4.52 (Ubuntu) Server at 127.0.0.1 Port 80</address> </body></html>
That should do it!
Conclusion:
- ModSecurity is a powerful open-source web application firewall (WAF) that offers an extra layer of security to detect and prevent attacks before they reach the web application.
- Following the installation steps outlined above, you can successfully set up ModSecurity with Apache on Ubuntu Linux.
- OWASP ModSecurity rules, when applied, provide recommended security settings to protect your applications further.
- After completing the installation and configuration, you can verify the functionality of ModSecurity by testing it with a sample HTTP request.
- Your feedback is welcomed, and please feel free to use the comment form below to report any errors or add additional insights.
What is mod_security in Apache?
ModSecurity is the standard open-source web application firewall (WAF) engine. Originally designed as a module for the Apache HTTP Server, it has evolved to provide HTTP request and response filtering capabilities across a number of different platforms including Apache HTTP Server, Microsoft IIS and Nginx.
Is ModSecurity a good WAF?
Why use ModSecurity? Web Application Firewalls are often the first line of defense against HTTP attacks on web applications and servers. The ModSecurity WAF is widely used for this purpose along with the Coraza WAF, also provided by OWASP.
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Richard
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Richard, a writer for Geek Rewind, is a tech enthusiast who loves breaking down complex IT topics into simple, easy-to-understand ideas. With years of hands-on experience in system administration and enterprise IT operations, he’s developed a knack for offering practical tips and solutions. Richard aims to make technology more accessible and actionable. He's deeply committed to the Geek Rewind community, always ready to answer questions and engage in discussions.
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